With the recent approval of the U.S. Food and Drug Administration (FDA), a human clinical trial is set to begin on BCG, a vaccine typically used to prevent tuberculosis, to treat fibromyalgia.

BCG, or Bacillus Calmette-Guerin, has been used since 1921 as a TB vaccine in countries with a high prevalence of TB. One particular type, or “species,” of BCG is also used to treat bladder cancer. Some studies have shown promise in BCG’s ability to potentially treat type 1 diabetes and multiple sclerosis by enhancing the immune system’s ability to fight its own diseased cells — a process known as immunotherapy.

The trial is funded by EpicGenetics, a biomedical company that also manufactures a blood test for fibromyalgia called the FM/a Test. Research by physician and EpicGenetics CEO Bruce Gillis suggests that fibromyalgia is an immune system disorder that causes patients to have abnormal white blood cells that produce irregular quantities of proteins called chemokines and cytokines, leading to inflammation. The test measures the levels of these proteins.

EpicGenetics released its FM/a test in 2013 and has faced criticism from skeptics, who say the research the test is based on is not consistent with other studies, and that the test doesn’t reliably distinguish fibromyalgia from other disorders with similar symptoms. EpicGenetics conducted a follow-up study comparing patients who took the FM/a test to patients with lupus and rheumatoid arthritis and a control group and found “statistically significant differences” between the patients, which Gillis said supports the test. He also said further research will be done to see if the test can be used to diagnose people with myalgic encephalomyelitis/chronic fatigue syndrome.

The BCG trial builds on EpicGenetics’ previous research. Gillis told The Mighty he believes BCG will “retrain” stem cells so they stop producing abnormal white blood cells and start producing normal white blood cells, thus producing normal proteins and potentially eliminating fibromyalgia symptoms. The trial will use a species of BCG called the Tokyo species, different than the species used to treat bladder cancer, which Gillis believes has the biologic activity needed to reverse immune system abnormalities.

“It’s like being in a sword fight with no shield — that’s what patients with fibromyalgia are afflicted with,” Gillis said. “So now what we’re hoping is, we’re giving them the shield, they should now function normally, they should have healthy protein systems and hopefully if all goes well their symptoms should disappear.”

If BCG treatment is successful, it would be different than the drugs currently available for fibromyalgia, which include antidepressants like Cymbalta and the anti-seizure medication Lyrica. These drugs may help treat fibromyalgia symptoms, but do not address the biology of fibromyalgia itself.

Trial participants will go to Massachusetts General Hospital to receive the BCG injections. Gillis said he does not expect there to be any side effects, and he believes two doses, spread 12 months apart, may provide a “lifelong benefit.” The FDA will not need to approve BCG as a drug since it is already in use for other conditions, but before it can be used to treat fibromyalgia, the FDA will need to see indicators that the BCG is working.

Gillis said he hopes to recruit thousands of people to join the trial. In order to qualify, people must take EpicGenetic’s FM/a test, and if they receive a positive result (or have already taken the test and indicated they were interested in participating in future research), they can decide if they would like to volunteer to participate in the trial. The test costs $1,080 without insurance, though Gillis said Medicare, CHAMPVA, most PPO insurance plans and some HMO plans will cover it.

In addition to finding a potential treatment for fibromyalgia, Gillis said he hopes to continue legitimizing the condition and also researching whether there is a genomic pathway that explains why people contract the disease, similar to the BRCA1 and BRCA2 genes for breast cancer.

“Fibromyalgia is a real disease and we’ve got to change the mindset of healthcare professionals and people in general,” he said